Metal detectors (underground metal detectors) circuit In addition to the sensitivity adjustment potentiometer, there is no adjustment part, as long as the welding is correct, the circuit can work normally. Machine in the static, that is, the speaker is not audible, the total current is about 10mA, detection of metal speakers when the sound, the whole machine current up to 20mA. A new laminated battery can work for 20-30 hours.
New welding metal detectors (underground metal detectors) if not normal work, the first to check the circuit board of the components, wiring welding is wrong, and then measure the battery voltage and power supply circuit is normal, voltage regulator diode VD1 stable voltage 5.5~6.5v between, VD2 polarity do not weld back. Detect the first stage of the oscillating coil in the disc and do not weld the fault at the end.
Before the metal detectors are used, need to adjust the length of the probe rod, as long as the black gum through the loose, push and pull the glue through the casing to the appropriate length, and then rotate the rubber inside the tube, so that the cable winding, and the tip of the handle to the top, and finally the black glue through the screw, lock the glue In this way, when holding the probe handle, the thumb is just close to the sensitivity regulator potentiometer.
To adjust the sensitivity of the metal detector, the detection disc (oscillating coil) to be far away from the metal, including the paper with aluminum foil, and then rotate the sensitivity of the potentiometer Knob (FINE tuning) to open the power switch, and rotate to half the position, and then adjust the coarse potentiometer knob (tuning), so that Finally, fine-tuned potentiometer, so that the speaker sounds just stop, when the metal detector is the most sensitive. When metal detectors are used to detect metal, the speaker will make a sound as long as the probe is near any metal, away from the point where the scream stops automatically.